We haven't heard all that much from them in this area of the world, but the AIDS denialist fraternity has caused undeniable heartbreak and misery amongst many groups and individuals, especially in South Africa.
What is wrong with denialism? As noted above, most denialists lack specific competences in relevant disciplines, and are prone to 'cherry picking' - they take isolated fragments of orthodox scientific research and then misuse it. For example, as Steinberg notes in his article, take "Kochs Postulates." One tenet argues that a causal agent must be present in all cases of consequent illness, which is the case with HIV and AIDS. Another argues that HIV should be isolated and grown in a pure medium, which has been done. Finally, accidents have led to HIV exposure, and antiretroviral drugs significantly slow down the spread of HIV and later development of AIDS.
Denialists also argue about the toxicity of antiretroviral agents, whose side effects have become less apparent as new forms of medication and combination therapies become available. In any case, some HIV+ people may chose to live with tolerable side effects if the outcome is an extended lifespan, as I do with antidepressants and their side-effects in my own life.
They also claim that theres is no widespread HIV/AIDS western epidemic, which ignores the suffering of HIV+ sub-Saharan African heterosexuals and western gay men alike. It also discounts collective prevention methods like safe sex and needle exchanges in western societies, as well as viral mutations that mean that the strain that infected sub-Saharan straight Africans may not be the saem one that western gay communities have experienced.
Finally, AIDS is said to be 'caused' by poverty and malnutrition. Certainly, poverty and malnutrition hasten morbidity and mortality through the absence of primary and public health services, prior immune system compromises and absence of ARV medication, but it is HIV that causes the suffering in that admittedly grim context. In any case, even African political leaders have lost their children and grandchildren to the epidemic.
Former South African President Thabo Mbeki is one particularly glaring example. He accepted the word of AIDS denialists, and an estimated 365,000 mostly black HIV+ South Africans had early deaths because his government didn't provide ARVtherapiesfor them, although his successor, Jacob Zuma, is more humane.
Duesberg himself has made homophobic statements about the non-'criminality' of homosexuality as a causal agent for the spread of AIDS in western societies, and today, his work is primarily published and defended by scientifically illiterate social conservatives, such as the right-wing Heritage Foundation, Regnery Publishing and creationist Phillip Johnson.
Jonny Steinberg: "AIDS Denialists" New Scientist 30.06.09: 32-36